Large Number Of Traits Research Articles

Enhanced efficiency of quantitative trait loci mapping analysis based on multivariate complexes of quantitative traits.

An approach to increase the efficiency of mapping quantitative trait loci (QTL) was proposed earlier by the authors on the basis of bivariate analysis of correlated traits. The power of QTL detection using the log-likelihood ratio (LOD scores) grows proportionally to the broad sense heritability. We found that this relationship holds also for correlated traits, so that an increased bivariate heritability implicates a higher LOD score, higher detection power, and better mapping resolution. However, the increased number of parameters to be estimated complicates the application of this approach when a large number of traits are considered simultaneously. Here we present a multivariate generalization of our previous two-trait QTL analysis. The proposed multivariate analogue of QTL contribution to the broad-sense heritability based on interval-specific calculation of eigenvalues and eigenvectors of the residual covariance matrix allows prediction of the expected QTL detection power and mapping resolution for any subset of the initial multivariate trait complex. Permutation technique allows chromosome-wise testing of significance for the whole trait complex and the significance of the contribution of individual traits owing to: (a) their correlation with other traits, (b) dependence on the chromosome in question, and (c) both a and b. An example of application of the proposed method on a real data set of 11 traits from an experiment performed on an F(2)/F(3) mapping population of tetraploid wheat (Triticum durum x T. dicoccoides) is provided.

Stereotypes and Self-ratings among Finnish Dancers

The purpose of this study was to examine incidences of stereotype traits associated with four types of dancer: a folk dancer, competitive ballroom dancer, ballet dancer and modern dancer. Evidence was gathered from each of these types to test dancers' views on their own stereotype traits (in-group's traits) and those related to the other types of dancers (out-group's traits). The study compared each dancer's self-rating to the ratings of others both in the same group and in the other three groups. The study used 308 non-professional dancers as subjects. They were all given a list of 28 traits and were asked to assign the traits they perceived to be typical for the four groups and for themselves individually. The dancers' in-group and out-group ratings for the 28 traits applied to the four groups differed significantly. There were fewer differences between the ballet and modern dancers' ratings of in-group and out-group stereotypes than for those of folk and ballroom dancers. Dancers assigned a larger number of traits as typical for their own group than for the out-groups. This supports the hypothesis of dancers' tendency to underestimate out-group variability relative to in-group variability (i.e. the out-group homogeneity effect). Also, in-group stereotype traits were seen in a more positive light than those of out-groups. Finally the implications for dance educators are discussed.

Total merit indices in dual purpose cattle

Abstract. The economic efficiency of dual purpose cattle is influenced by a large number of traits which may be classified in groups of dairy, beef and functional traits. The combination of estimated breeding values for single traits in a total merit index, as long practised in some Scandinavian countries, is currently being implemented in a number of Central European states. Economic values for populations of dual purpose cattle in Austria derived from a deterministic herd model are presented. Traits in the dairy group are fat and protein yield; beef traits are daily gain, dressing percentage and carcass conformation; functional traits are longevity, persistency, fertility, calving ease, stillbirth and somatic cell count. A rough average over populations of the relative economic importance of dairy vs. beef vs. functional traits is 37:18:45 (economic weights of the traits are scaled with their genetic Standard deviations, differences in expression of traits are taken into account). Due to the covariance structure of the traits most of the gain is expected for fat and protein yield (moderate heritabilities and high positive correlation of the two traits). The proportions in expected monetary gains from the three sets of traits are 81:9:10. Omission of beef and functional traits from the index would lead to a 13 percent loss in total merit and negative responses for beef and functional traits. Inclusion of conformation as an early predictor of longevity has very little effect on total merit. The indices presented are compared with total merit indices used in other European countries.

The Three Faces of Love: College Students' Perception of the Spouse, Date and Cross-sex Friend

The present article explored the perception of spouse, date and cross-sex friend among the college-going youth. Six demographical, 14 physical and 25 psychological characteristics were selected from a larger number of traits generated in a preliminary study on 200 college students. In the final study these traits were presented to 240 college students who rated them in terms of their desirability in either a spouse, or a date or a cross-sex friend. Responses to the demographical variables were obtained on a multiple-choice response format with qualitative categories. The physical and psychological characteristics were assessed through responses to the items on five-point Likert-type scale. Results indicated that women put greater emphasis on demographical features and psychological characteristics, while men emphasised physical traits. Perception of the wife by the men was a combination of sex object and nurturing object, while a date was a companion without much commitment. For the women a husband and a date possessed overlapping characteristics, dates having greater sexual appeal. Cross-sex friends for both sexes shared some characteristics of spouse and date in less intensity. Results have been interpreted in terms of the evolutionary versus learning model of love.

An eXceptional chromosome

Is there a relationship between a gene’s function and its location in the genome? For the most part, the evidence that genes are non-randomly distributed about the genome is little more than suggestive and rarely more than anecdotal. In guppies, it has been shown that a large number of traits that contribute to male sexually dimorphic features map to the Y chromosome1. Similarly, Lahn and Page2 have shown that the human Y chromosome contains many spermatogenesis-specific genes. More recently, however, the first really systematic analyses have shown up a number of non-random patterns of gene distribution, and all of them show the X chromosome to be unusual.

Molecular-marker analysis of quantitative traits for growth and development in juvenile apple trees

Random amplified polymorphic DNAs (RAPDs) were used in combination with a double pseudo-testcross mapping strategy to estimate the position and effects of quantitative trait loci (QTLs) for traits influencing juvenile tree growth and development in two apple cultivars. The mapping population consisted of 172 F1 trees from a cross between the columnar mutant ‘Wijcik McIntosh’ and a standard form disease-resistant selection NY 75441-58. Significant associations were found between markers and height increment, internode number, internode length, base diameter increment, base diameter after 9 years of growth, branch number, and leaf break. The number of genomic regions associated with each trait varied from one to eight. The amount of variation explained by linear regression on individual marker loci (R2) ranged from 3.9 to 24.3%, with an average of 7%. Multiple regression using markers for each putative QTL explained from 6.6 to 41.6% of the phenotypic variation, with an average value of 24.3%. A large number of traits had significant variation associated with the map position of the dominant columnar gene, Co. QTL stability over years was estimated by comparing the locations of putative QTLs for traits measured in multiple years. The majority of genomic regions were associated with a trait in only a single year, although regions associated with a trait in more than 1 year were also detected. The limitations of dominant markers and an outbred mapping pedigree for QTL analysis are discussed.

DESIGNING EXPERIMENTS TO MAXIMIZE THE POWER OF DETECTING CORRELATIONS.

Studies investigating correlations among traits are increasingly common in evolutionary biology. By providing power calculations, minimum sample sizes, and standard errors of correlation coefficients in a variety of contexts, this note provides guidelines to insure that nonzero correlations will not be erroneously dismissed as nonsignificant in properly designed experiements. Forty individuals is often sufficient for reasonable estimation of correlation coefficients, although 100 or more individuals may be nexessary if a large number of traits are involved or comparisons are to be made among the coefficients.

Relationship between species relative abundance and plant traits for an infertile habitat

This study tested whether differences in species abundance at an infertile site could be explained by differences in the species' plant traits. Nine traits were chosen for the analysis based on results of previous studies conducted across soil fertility gradients. The traits were measured for each of seven herbaceous species whose abundance ranged from 5% to 100% of locations occupied in a ridgetop habitat. Using linear regression, significant relationships were found between species relative abundance and each of five traits. In these relationships, a trait explained between 69% and 88% of interspecific variation in abundance. Relatively abundant species had a slower growth rate, smaller shoot mass, higher root to shoot ratio, slower loss of leaf tissue to herbivores and higher infection of roots by mycorrhizal fungi than less abundant species. Using three of these five traits (i.e. shoot mass, mycorrhizal infection and loss of leaf tissue to herbivores) as independent variables in a multiple regression equation explained 99% of interspecific variation in abundance. The latter result indicates that species relative abundance can be explained for a single habitat by choosing traits found to be related to species abundance in previous gradient studies. However, not every trait chosen was significantly related to species abundance. Therefore, a large number of traits may have to be chosen initially to ensure that some subset of these traits can explain species relative abundance.

Complexity of the interpersonal self and affective reactions to interpersonal stressors in life and in the laboratory

Self-complexity refers to the number and interrelatedness of a person's conceptions of himself or herself. In both a naturalistic survey and a laboratory study, we applied self-complexity theory to test a marker of cognitive vulnerability to interpersonal stress, specifically the aspect impact quotient (AIQ) of the interpersonal self. A high interpersonal AIQ reflects an interpersonal self with a large number of traits that are dispersed among other self-aspects. In Study 1, we found that subjects with high compared with low interpersonal AIQ became more dysphoric after the experience of real-life interpersonal (friend) stressors, and that this effect was unique to interpersonal AIQ, In Study 2, we hypothesized that affective reactions to interpersonal acceptance or rejection in the laboratory would be more extreme for individuals with high compared with low interpersonal AIQ. Analysis of positive affect revealed the hypothesized effect for AIQ × Outcome, and this effect was unique to interpersonal AIQ. However, subjects' negative affect was unrelated to their interpersonal AIQ. Overall, the results of these two studies suggest that the relative structure of each individual's interpersonal self influences his or her affective reactions to interpersonal events, and that self-complexity theory, applied to a specific self-aspect, can contribute to an understanding of stress vulnerability.

Value of various taxa in breeding tetraploid blueberries in Florida

Many species and races of blueberries native to the southeastern United States have been used in the University of Florida breeding program. Highbush blueberry cultivars from a program started in 1908 in the northern United States were used at the start of the Florida program as a source of early ripening, large fruit size and high fruit quality. Vaccinium species native to Florida were used to obtain adaptation to the Florida environment, which is characterized by a long growing season, mild winters interrupted by killing freezes, low number of chill hours, and warm, moist conditions that favor fungal pathogens. The Florida species that have proved most useful in breeding have been southern races of Vaccinium corymbosum, which produce hybrids with high vigor and upright growth habit, and V. darrowi, which produces hybrids that retain their leaves late into the winter and have a very low chilling requirement. Species that have been less useful in breeding are V. elliottii and V. myrsinites. V. arboreum, in Vaccinium section Batodendron, is the only species outside of section Cyanococcus that has been used in breeding Florida blueberries, and has been a good source of vigor and tolerance to soils low in organic matter and high in bicarbonates. Although the gene pool available for improving low-chill highbush blueberries is large and diverse, progress is slowed by the need to improve simultaneously a large number of traits.

Assessment of the Full Content of Physique Stereotypes with a Free-Response Format

A major limitation of physique stereotyping research is that American subjects have used a restricted set of traits provided by the experimenter to evaluate endomorphs, mesomorphs, and ectomorphs. A free-response procedure was used in Study 1 to identify the full domain of traits associated with each physique. Although many of the traits identified were similar to those used in previous research, a number of new trait dimensions were uncovered. In Study 2, the large number of traits generated with the free-response format was reduced by combining synonyms. This new set of traits was placed in semantic differential format and given to a new sample of subjects to evaluate. The results paralleled those of the first study with the exception that ectomorphs were seen more favorably. This discrepancy, as well as the fact that raters listed trait antonyms within each of the three major physiques in Study 1, suggests the possibility of unique subtypes within the global stereotypes. Examples of these subtypes are proposed.

An Advantage of Sexual Reproduction in a Rapidly Changing Environment

When an environmental change imposes strong directional selection, there are two advantages of sexual reproduction. First, an asexual population is limited to the most extreme individual in the population, and progress under directional selection can go no farther without mutation; no such limitation applies to a sexual population. Second, more quantitatively, directional selection in an asexual population monotonically decreases the variance, whereas the variance of a sexual population quickly reaches a steady value; this difference remains even if the direction of selection occasionally changes. With realistic environmental changes small alterations in any particular measurement or trait are usually sufficient to keep up with the changes, but fitness, since it depends on a large number of traits, will be selected with greater intensity, which may be enough to confer a distinct advantage on sexual reproduction. This applies particularly to a large or rapid environmental change. Eventually mutation will enhance the variance, but by then it may be too late to prevent extinction of asexual strains.

Interrelations among vegetative, yield and bunch quality traits in short-tem oil palm progenies

Breeders usually obtain information on a large number of traits in their breeding and selection programmes. However, since some or many of these traits could be related, it is desirable to reduce the number being handled to the barest minimum without sacrificing efficiency. Breeders often use correlations, stepwise multiple regressions and path coefficient analyses to determine the nature of relationships among such characteristics. The objective of this study was to use these statistical methods to determine traits that could be useful in predicting number of bunches (NB), fresh fruit bunch yield (FFB) and mean bunch weight (MBW) for 13 backcross progenies of oil palm (Elaeis sp.) grown in four replications with 12 palms per replication. Data were collected over a period of 3 or 11 years, depending on the trait. Progeny means and individual palm data, averaged across replications and years, were used for each of these analyses.

Impact of the new statistical technology on pig improvement

AbstractPast improvement programmes in pigs have concentrated on lean growth, and have relied on direct comparisons of contemporaries in a common environment. The new mixed model technology now allows comparisons across environments and generations, and, by utilizing all possible genetic relationships, more accurate prediction of genetic merit for traits of low heritability. In addition, breeding programme design will benefit from more precise estimation of genetic parameters. Principal benefits of the new technology are greater flexibility of structure of breeding programmes, and faster improvement of litter size. The consequence will be larger populations under selection with lower costs per unit of genetic improvement. For national improvement schemes using a high proportion of AI matings, central testing stations could become unnecessary. Main research priorities are the optimum family structure to balance selection and inbreeding, more efficient computing strategies for large numbers of traits, and the incorporation of single genes into predictions of merit. The new technology will be important for the exploitation of biological advances in manipulation of both reproduction and the genome.

Self-Versus Other-Referent Processing at Encoding and Retrieval

The interactive roles of encoding and retrieval processes were examined in relation to self-versus other-referencing in an incidental recognition-memory experiment. At encoding, subjects made either a self-or other-referent judgment about each of a large number of traits. At test, retrieval cues were varied by having subjects make a self-referent judgment, an other-referent judgment, or no judgment about each original trait plus an equal number of new traits. The trait words were more accurately recognized when retrieval cueing reinstated the original encoding context (whether self-or other-referent) than when it instated the other context. In addition, although self-referent encoding yielded better memory than other-referent encoding in the self-referent and no-cue retrieval conditions, other-referent encoding yielded equally good memory in the other-referent retrieval condition. Although self-referent trait judgments were more consistent than other-referent judgments, consistency did not mediate the memory effects. It was suggested that the greater efficacy of self-referent encoding may stem in part from the interactive roles of encoding and retrieval operations in conjunction with a habitual tendency to process trait information with reference to the self